Pneumatic tool.



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unirsi) stra-Tias PATENT clarion.

' THOMAS DONOHOE, OF AVLLA, PENNSYLVANIA. i

Appiicaab'n med september 12, 1901. serial No. 392,522.

Td all whom ,it may concern:

Bc it known that I, THOMAS DoNoHoE, a resident of Ayella, in the county of Washington and State of Pennsylvania, have invented. certain new :ind useful Improvements in Pneumatic Tools, of which' the following is a specification. s Y

This invention relates to that typ of ort-- able pneumatic tools, such as riveting iammers, chippcrs etc., .which when in use are held in close engagement with the Work, thus preventing the riveting, chipping or other tool from being driven out of the' forward end of the cylinder by the blows from-the hammer piston. Tools of this character are not available for drilling, as when bdrin'g holes in or through coal and other substances, as in such use it is maniestly impossible tmkeep the front end of the rapidly operating tool in con-l sant engagement with the work, its rogress through the material being too papi to perfmit 'of this. And even if 1t were possible to thus maintain thetool, itis clear that when the tool has worked its way through the material it would be projected entirly clear of the cylinder, this in the absence of means for llmitin the outward movement of the tool in\ the cylinder. Furthermorefwith hammers, chippers, etc., as now constructed and operated, the tool is in engagement with the work when the blows are delivered by the hammer piston, resulting in a dead 'or solid impact.

In drilling coal,'etc., it is desirable to have the tool thrown forward ava-inst the work in response to each blow ofthe hammer piston and to have it retracted. after each blow and in initial orstarting position for each subsequent blow. Als'o 1n work of this character it is necessary to limit the outward movement of the'tool, for in the absence of limit'- ing means it would soon be rojected entirely clear of the cylinder. With these objects in view, I` have rovided an ordinary portable hand-held tool with s. tool or drill holder having a pistonwhich operates in a piston chamber`at theouter end of the tool c linder, with nieans. preferably controlled y the tool ,holder for admitting compressed airin iront of the piston on ea'ch stdaire of the tool and just before it rca-ches the outward limit of its movement, the air Ybusadmitted operating o the holder and toreturn it to inward or starting position. Y

'Inthc accompanying drawings, Figure 1 1s a View partlylin sideelevation and artly in section of a portable pnermatic too eonrNEUmTIc Toor..

Patented au g. 4, 199s.

structed in accordance with the invention.-

Fig. 2 is a longitudinal sectional view on a. larger scale of the outer portion of the same,4

showing the to'ol holder retracted, and Fig. 3 60 is a similar view showing the samein extended osition.

eferring to the drawings, 2 designates the cylinder or body of a tool, 3 the handle .end'thereof, and 4 the hammer piston. All 65` of these parts may be constructed in accordance with any of the familiar dcsign's'of vportable hand-held tools of this character well known in the art.

Cylinder 2 .is made somewhat longer than 70 heretofore, with the outer end of its b ore closed by head 5, and inward from this head is head 6, with the space between these` heads forming piston chamber f? through which ex- Y tends stem 8 carrying at its outer end' the I5 holder or chuck 9 for drill or other tool 14. 'ghe inner portion 8" of stem 8 extends t rough an opening inl head '6 and recelves the blows from hammer piston 4 in the same manner that the blows are imparted to the Su .inner end or shank of the chisel or other tool in-the present familiar forms of implements of this character. 5 .f

Secured to stem 8 within chamber 7 is iston 10, and opening into the forward en 'of 85 the chamber at 11 is duct 11' in the. wall of the cylinder 2 which extends toward the handle end thereof where itr isopen to the sourceof compressed air. This u ct is also extended throughthc outer extremity of 'J0 cylinder 2, and movable therein is valve 12 which is secured to and movable with holder or chuck 9,-,this` valve being in the form of a in which operates to clo'se communication etween the duct and chamber 7 when the v5 tool holder is in inward position, and which opens said duct to the chamber when the -tool holder and piston 10 approach the outward limit of their movement in response t .a blow from hammer piston' 4. And with. 1011 on piston 10 throws itA and the holder or 10-5 chuck backward or inward to starting position, the action in this regard being as ra id as the strokes of hammer piston 4,' so t at stem projection 8 is in position to receive each forward biow oisaid piston. Chamber -110 7 maybe provided withport 13 fore'ihaustingi from the rear end of chamber 7 to relieve any valve openinfJr on the outward stroke of the pressure that might otherwise occur on the holder and closing on the inward stroke. rear face of piston 10 due to the passage of 4. In apneumatic tool, the combination of 50 air through head 6 and around stem 8' intoa reciprocating tool holder, a cylinder and a. 5 chamber 7. pistontherein for effecting the retraction of With the implement thus constructed, it the holder, a compressed air duct leading to is necessary to noltl the tool against the face the cylinder with a valve passage intercept. of the work to confine the tool within the ing the duct, andapin-like valveinsaid 'as- 55 cylinder. And in addition to-controlling th sage fixed to and movable with the toolho der lo outward movement of the tool, the latter and and operating to open and close'said duct. A 5.

the bloW-receigfstem are returned after n a pneumatic tool, the combination each, blow and in position to receive the next with the cylinder and the hammer piston, of im actfiom the hammer piston. The energy atoolholder adapted toreceivetvvard blows 60 uti izedin r'etractin'g the tool is wholly infrom the hammer piston, and air pressure de cndent ofthe Working stroke and its immeans controlled by the movement' of the peiling force, no portion ofthe latter be'mg holder for ret-resting. thelatter-after each i consumed or stored for retracting the tool blow.

as is the casein those forms of apparatus in 5. In a neumatic' tool, the combination of 65 which' a tool-retracting spring is compressed a tool bo y, a tool holder, means within the 2o by the `working stroke. -j bodv for imparting outward blows. to the I claim i 1 holder-,a piston secured to the holder, acharn-` 1. The combination with the bloW-impartber in which s'aid piston moves with a. passage ing hammer of a neumatic tool and housing for compressed air leading to the outer end o f 70 therefor, of'a toolholder movable independthe chamber, and a valve movable With th' 2. ently of the hammer and adapted to receive holder'for closing and opening said passage. tool projecting blows therefrom, a suitably 7. In a pneumatic tool, the com inatlon reused piston movable with the Atool holder, with a cylinder, the hammer pistontherein,

and meansactuated by the forward move- -and compressed air connections and --valve- 75 ment of the tool holder for subjecting said 'mechanism for controlling the movement ,of piston to tool-retracting air pressure: l the hammer piston, of a tool-holder adapted '2. `In a T)neumatio tool,I the combination of to receive outward blows from the hammer tool holder, means for im arting tool-pro-f piston, a. piston movable With the holder, a. ject-ingblowsthereto,asuitaliulyhousedpiston chamber in which said piston moves, the ,80 rigid with the holder ivith an air duct extendcylinder having s duct communicating at its ing to the housing and a valve passage interupper end with the compressed air connecsecting saidduct, and a valve 1n the passage arranged 1n a plane parallel With the plane of movement o the tool holder and secured thereto and closing the ductand excluding tool-holder-retracting airressure from the housing save when the hol er and valve are in outward position.

3. in a neumatic tool, the combination of a. tool hol er, a piston secured thereto, a cyltion andjit its lower end with the outer end of said piston chamber, 'the duct being extended to the outer end of the cylinder, and a 85 pin secued to the holder and littinff the duct and closing the same to the 'chanilner when the holder is in inward position.

In testimony whereof I ailx my signature in prcsence'of two Witnesses.'

'morals DoNoHori.vv

inder in which the piston moves, a com- Witnesses:

pressed air inlet for the cylinder, and a valve L. M. IRWIX, DON J. Hrm.;

orthe inlet rigid with the tool holder, the 

